Sewing machine frame construction

ABSTRACT

A sewing machine frame construction comprising a bed portion and a bracket arm portion which are fabricated separately and joined along accurately located planar mating surfaces extending lengthwise of the sewing machine frame substantially parallel to the path of needle reciprocation, and a sewing head portion in which the needle is guided for reciprocation, said sewing head portion being fabricated separately and joined to the bracket arm portion along accurately located planar mating surfaces extending substantially perpendicular to the plane of the mating surfaces between the bed and bracket arm portions, and fastening means for securing said sewing head portion to said bracket arm portion with limited capacity for angular adjustment therebetween to locate the path of needle reciprocation accurately with respect to a reference point on said bed portion.

[4 1 Feb. 18, 1975 United States Patent [1 1 Adams et al.

[ SEWING MACHINE FRAME Primary Examiner( ie0rge H. Krizmanich CONSTRUCTION [75] Inventors: Kenneth D. Adams, Madison;

Walter F. King, Little Silver, both of N].

7] ABSTRACT A sewing machine frame construction com parately ns, and

prising a bed portion and a bracket arm portion which are fabricated separately and joined along accurately located planar mating surfaces extending lengthwise of the sewing machine frame substantially parallel to the path of needle reciprocation, and! asewing head portion in which the needle is guided for reciprocation, said sewing head portion being fabricated se and joined to the bracket arm portion alo g accurately located planar mating surfaces extending substantially perpendicular to the plane of the mating surfaces between the bed and bracket arm portio 7 7 2/ 1 m W72 1 a b Y W 2 e 8 I y n w 3 D. mm l d m mm. m 0 um i C B mm" u 9 mm m g l n .m w m m m S W mmm h e 7 "A hY. a 5 mm m TN M 3 nu o .e e N l n CH .018 d M m M D. Sm k A F A UHF M an HUN 6 7 2 AL 555 NJL fastening means for securing said sewing head portion UNITED STATES PATENTS to said bracket arm portion with limited capacity for angular adjustment therebetween to locate the path of 112/259 I 2/258 X needle reciprocation accurately with respect to a ref- Pfaff 112/258 erence point on said bed portion.

Looker l/l890 Dimond et al.... 10/1934 10 Claims, 7 Drawing Figures PATENI'EQ FEB I 81975 sum 1 OF 3 PATENTEU v 3,866,553 saw 3 ur 3 1 SEWING MACHINE FRAME CONSTRUCTION BACKGROUND OF THE INVENTION The most conventional mode of sewing machine frame construction involves fabrication of two portions, the bed portion and an integral bracket arm and sewing head portion. While clamped in a fixture which orients the path of needle reciprocation, as dictated by the sewing head portion, relatively to a reference point on the bed portion both longitudinally and laterally along the bed, accurate, usually tapered drift pin holes, are formed between the bed and bracket arm to main tain the alignment in which orientation the two frame parts are secured together. There are a number of disadvantages to this conventional sewing machine frame construction. It is expensive, since relatively massive fixtures are required and the locating holes must be formed while the fixtures are being used so that these manufacturing steps become awkward and time consuming. Moreover, this conventional construction utilizes an appreciable amount of space within the critical area at the juncture of the bed and bracket arm portions of the sewing machine frame and thus detracts from the availability of this space for other mechanisms of the sewing machine. Furthermore, this conventional form of construction can give rise to an unsightly joint 1 between the bed and bracket arm portions because the position of the parts is oriented with respect to the path of needle reciprocating and not with respect to the adjacent surfaces on the arm of the bed.

Other sewing machine frame constructions are known where the frame is made in two halves divided vertically along the machine center line. Here the disadvantage is encountered that no provision other than selective assembly or physical deformation of the parts is made for compensating for tolerance variation as between the different parts.

SUMMARY OF THIS INVENTION It is an object of this invention to provide a sewing machine frame construction which can be made economically without requiring complicated, bulky, or awkward fixtures, without requiring physical deformation or selective assembly of the parts, and in which close registration of both external frame joints as well as orientation of the path of needle reciprocation may be easily obtained. This object of the invention is attained by fabricating the sewing machine frame in three portions including a bracket arm portion and a bed portion having mating surfaces located in a generally vertical plane which extends lengthwise of the sewing machine frame and substantially parallel to the path of needle reciprocation, and a sewing head portion joined to the bracket arm portion along a planar mating surface arranged substantially perpendicular tp the plane of the mating surfaces between the bracket arm and bed portions. Upon assembly, the generally vertical planar mating surfaces between the bracket arm and bed frame portions will orient the path of needle reciprocation within a plane extending transversely of the sewing machine bed and containing the predetermined reference point through which it is desired that the path of needle reciprocation shall pass. By the provision of fastening means between the sewing head and the bracket arm portions of the frame which fastenings have the capacity for accommodating angular adjustment of the sewing head relatively to the bracket arm portion, the path of needle reciprocation may be oriented easily through the predetermined reference point using only rudimentary gauges.

Another object of this invention is to provide a sewing machine frame construction as described above in which the critical space at the juncture of the bed and bracket arm portions of the sewing machine frame is relatively free of encumbrance by fastening means therebetween and in which simply oriented interacting elements on said bed and bracket arm portion may be provided remote from the juncture thereof for strengthening the assembly of these sewing machine frame portions.

DESCRIPTION OF THE DRAWINGS A preferred embodiment of this invention is illustrated in the accompanying drawings in which:

FIG. 1 is a disassembled front perspective view of the sewing machine frame parts made in accordance with this invention,

FIG. 2 is a rear elevational view of the sewing machine frame portion of FIG. 1 in assembled relation,

FIG. 3 is a head end elevational view of portions of the assembled sewing machine frame of FIGS. 1 and 2,

FIG. 4 is a disassembled bottom plan view of the sewing machine bed portion and of the sewing machine bracket arm portion,

FIG. 5 is an assembled bottom plan view of the sewing machine bed portion and bracket arm portion and includes an illustration of certain of the sewing machine drive and actuating mechanisms which are carried in these sewing machine frame parts,

FIG. 6 is an end elevational view of the assembled sewing machine frame illustrated in FIG. 5, and

FIG. 7 is a disassembled perspective view of a sewing machine bed and a fragment of a sewing machine bracket arm made in accordance with this invention and illustrating a modified form of the construction.

In accordance with this invention, the frame portion of a sewing machine is constructed in three separate units including a bed portion indicated generally at 11, a bracket arm portion indicated generally at 12 and a sewing head portion indicated generally at 13. These sewing machine frame portions are illustrated in disassembled relation in FIG. 1, 4, and 7 and are illustrated in assembled condition in the remainder of the figures.

Referring to FIG. I, the bed portion 11 of the sewing machine frame is formed with a work supporting surface 20 in which a recess 21 is provided which accommodates a loop taker 22 driven by a bed shaft 23. A part of the recess 21 is covered by a throat plate 24 which provides a removable extension of the work supporting surface 20 above the loop taker. The throat plate is formed with a needle aperture 25 which defines a restricted area through which a needle 26 must reciprocate for cooperation with the loop taker in the form ation of stitches. The throat plate 24 is also formed with slots 27 through which the limbs of a feed dog 28 move into and out of contact with work on the work supporting surface to feed the work in a direction parallel to the slots 27 i.e., transversely across the bed. As shown in FIGS. 3 and 5, the feed dog 28 is carried by a feed bar 29 forming a pair of a conventional four-motion feed mechanism adapted to derive work feed motion from a feed shaft 30 driven from the bed shaft 23.

' ing mechanism of the sewing machine therein. Since this invention is concerned with the sewing machine frame construction, only those fragments of the sewing instrumentalities and actuating drive and control mechanisms therefor are illustrated which will assist in a full understanding of this invention, it being understood that the frame construction of this invention can accommodate any conventional form of such stitch forming instrumentalities and associated mechanisms.

As shown in FIG. 1, an arm shaft 31 is journaled in the bracket arm portion 12 and carries a counterbalanced crank 32 embraced by a needle reciprocating link 33. As shown in FIG. 6, the arm shaft 31 also carries a driven pulley 34 on which a drive belt 35 is entrained from an electric motor 36. The arm shaft also carries a sprocket 37 on which is entrained a timing belt 38 which extends to a sprocket 39 on the bed shaft. Idler pulleys 40 and 41 in the bracket arm 12 serve to delineate a path for the timing belt 38.

The sewing head portion 13 of the sewing machine frame, as shown in FIGS. 1,2,3 and 6, is generally C shaped with an upper arm 50 and a lower arm 51 extending from a base section 52. The upper arm 50 carries a bearing sleeve 53 formed with a spherical seat, while the lower arm 51 carries a spherically shaped trunnion 54. A needle bar gate 55 which is provided with upper and lower bushings 56 and 57 in which a needle bar 58 is endwise reciprocable, is mounted so as to swing in the sewing head for which purpose the upper needle bar bushing 56 is spherically contoured to cooperate with the bearing sleeve 53 while a spherically recess 59 is formed adjacent to the lower bushing 57 to accommodate the trunnion 54.

A spherically headed pin 60 carried by the needle bar gate passes through a clearance opening 61 in the sewing head frame portion 13 and may be engaged by a drive link 62 from any conventional zigzag driving mechanism for imparting lateral jogging movements to the needle bar. A drive stud 63 carried by a block 64 secured to the needle bar 58 is adapted to be embraced by the drive link 33 for imparting endwise reciprocatory movements to the needle bar.

The manner in which the bed 11 and bracket arm 12 portions of the sewing machine frame are oriented and secured together will now be described. As shown in FIGS. 1,4, and 5, the bed 11 is formed with two bosses 100, 101 spaced apart longitudinally along the bed, i.e. at different distances from the loop taker. The exposed surfaces of these spaced bosses 100, 101 are machined accurately in a common plane denoted X-X in the drawings and arranged substantially perpendicular to the work supporting surface 20 of the bed, that is, sub stantially vertical when the machine occupies a conventional position for use. As shown in FIG. 5, the plane X--X is preferably located completely rearwardly of the loop taker 22 in the bed.

The bracket arm portion 12 of the frame is formed with bosses 1 10, 111 spaced apart the same distance as the bed bosses 100, 101 and machined accurately in a common plane so that the contiguous surfaces of the bosses 100,110 and 101, 111 define a first set of planar mating surfaces when the bracket arm and bed portions of the machine frame are assembled.

The bracket arm and bed portions of the machirr. frame are adapted to be oriented relatively to each other by locating pins 120 set into aligned bores 121 formed through the contiguous sets of bosses 100, 110

4 and 101, 111 substantially normal to the plane X-X. The bracket arm and bed portions are secured together by threaded bolts 122 which threadedly engage tapped holes 123 in'the bosses 110 and 111 of the bracket arm portion 12 of the frame and pass through clearance holes 124 in the bosses and 101 of the bed.

The bracket arm and sewing head portions of the machine frame are oriented and secured together as will now be described. As shown in FIG. 1, the bracket arm 12 at its free extremity overhanging the bed is formed with an accurately machined planar surface 130 arranged substantially in a plane designated YY which is perpendicular to the first set of planar mating surfaces as represented by the plane X-X in the assembled sewing machine frame. As shown in FIG. 1, therefore, the plane to which the surface of the bosses and 111 is machined is mutually perpendicular to the plane YY to which the surface is machined. The base 52 of the sewing head portion 13 is similarly machined with a planar surface which in the assembled condition of parts is contiguous to the surface 130 on the bracket arm portion 12 and defines therewith a second set of planar mating surfaces.

The bracket arm is formed with spaced tapped holes 150, 151 normal to the surface 130 and corresponding thereto the sewing head base 52 is formed with clearance hole snugly accommodating a fastening bolt threaded into the tapped hole 150 and formed with an elongated clearance hole 161 which accommodates a fastening bolt 171 threaded into the tapped hole 151. This arrangement provides for a limited range of adjustment of the sewing head portion 13 angularly relatively to the bracket arm portion 12 about the axis of the fastening bolt 170 for the purpose which will be described below.

In manufacturing a sewing machine in accordance with this invention, the locating pin holes 121 as well as the clearance and tapped fastening screw holes 123 and 124 in the bosses 100, 101 and 110, 111 of the bracket arm and bed portions are machined with the parts oriented only to the degree that the needle 26 in the sewing head assembled onto the bracket arm 12 will reciprocate within a plane Z-Z intersecting the restricted area through which a needle must reciprocate for cooperation with the loop taker, which restricted area is represented by the needle aperture 25 in the throat plate.

This orientation in only one direction may be accomplished with relatively simple gauges. Moreover, since the orientation involves only one direction, other aspects of orientation, such as the alignment of nonfunctional adjacent frame portions such as those indicated at in FIG. 2 may be included in the gauges thus eliminating the need for deep shadow lines and the like in the exterior design configuration to hide mismatches as were commonly required with prior sewing machine frame assembly techniques.

As a final step in the assembly of the sewing machine frame of this invention, the sewing head portion 13 is attached to the bracket arm portion 12 using the fastening screws 170 and 171. In so doing, the limited angular adjustment provided by the clearance hole 161 provides for alignment of the path of needle reciprocation to a position indicated at 0--0 within the plane Z-Z in which, as shown in FIG. 3 the needle will pass through the needle aperture 25.

A modification is illustrated in FIG. 7 in which the bed portion 11 of the sewing machine frame is formed with an elongated shape suitable for the reception of tubular articles, this being referred to in the art as a cylinder bed construction. In this modification shown in FIG. 7 the parts which are the counterpart of those in the other figures are denoted by similar reference characters with prime numbers. It will be noted that the construction of most of the parts is identical with that illustrated in the remaining figures but that the arrangement of the plane XX in which the first set of planar mating surfaces is formed on the bosses I00, 101', 110', and 1111' of the bed and bracket arm, respectively, is located along the rear edge of the cylinder bed 11'. The frame construction of this invention is, therefore, particularly well suited for sewing machines embodying the cylinder bed arrangement.

Referring to FIGS. 1,4 and 5, a feature of this invention is disclosed by which the juncture of the bed portion ll with the bracket arm portion 12.may be materially reinforced. To this end, the bed portion 11 is formed with a series of blade elements 200 each blade element being arranged parallel to the first set of planar mating surfaces XX. Moreover, the blade elements 200 are preferably located at the opposite side of the plane XX from the loop taker 22 of the sewing machine so as to avoid conflict with space requirements within the bed for the stitch forming instrumentalities and the actuating mechanism therefor. The blade elements 200 are spaced apart so as to provide socket recesses 201 therebetween. As also shown in FIGS. 1,4 and 5, the bracket arm portion 12 of the machine frame is similarly formed with blade elements 202 which are spaced apart to define socket recesses 203 therebetween, the blade elements 202 being oriented substantially parallel to the exposed surfaces of the bosses I and 111 which cooperate to define the first set of planar mating surfaces between the bracket arm and the bed. The blade elements 200 on the bed portion and 202 on the bracket arm portion are formed so that they will provide an interdigitated labyrinth in which the interleaved elements extend in spaced relation to each other when the bracket arm and bed portions are secured together as described above. The spaced relation between the blade elements 200 and 202, each being received with clearance in corresponding socket recesses 201 and 203 in the opposing frame portion, is significant in that the blade elements will not interfere in any way with the orientation and fastening of the bracket arm and bed portions. After the bracket arm and bed portions are oriented and fastened together as described above, one or more sets of aligned apertures 205 may be formed through the interdigitated blade elements 200 and 202 each of the axially aligned apertures accommodating a locking pin 206 which may be secured therein as by a slight force fit.

The present invention provides for a frame construction in which the joinder of the frame portions presents a minimum of obstruction to the clear space within the frame within which the actuating mechanism and driving devices for the stitch forming instrumentalities may be accommodated. The juncture of the bed portion and bracket arm portions, in particular, involves the need for spaced bosses 100, 101, 110 and 111 which prese..t a minimum of interference with the space in this area for the sewing machine motor 36 and for the driving connections between the motor and the sewing machine as well as the driving connections between the main drive shaft 31 and the bed shaft 23 as are illustrated in FIG. 6.-

Having set forth that, the nature of this invention, what is claimed herein is:

l. A sewing machine frame including a bed carrying a stitch forming loop taker and formed with a work supporting surface, a bracket arm formed with means for supporting mechanism above said bed, and a sewing head carrying an endwise reciprocable needle adapted to cooperate with said loop taker in the formation of stitches, a first set of planar mating surfaces formed on said bracket arm and on said bed, said first set of mating surfaces which are on said bed being substantially perpendicular to the work supporting surface thereon, means for fastening said first set of planar mating surfaces of said bracket arm and bed together in fixed pre determined relationship, a second set of planar mating surfaces formed on said sewing head and on said bracket arm, said second set of mating surfaces which are on said bracket arm being substantially mutually perpendicular to the first set of planar mating surfaces on said bracket arm, and means for securing said second set of planar mating surfaces on said sewing head and bracket arm together with limited capacity for adjustment therebetween in the plane of said second set of planar mating surfaces.

2. A sewing machine frame as set forth in claim 1 and including means for transporting work transversely across said bed, in which said first set of planar mating surfaces extend longitudinally on said bed.

3. A sewing machine frame as set forth in claim 2 in which the plane containing said first set of planar mating surfaces is offset transversely on said bed completely to one side of said loop taker therein.

4. A sewing machine as set forth in claim 3 in which said first set of planar mating surfaces is formed on interengaging pairs of bosses located on said bed and on said bracket arm respectively, said interengaging of pairs of bosses being spaced apart longitudinally of said bed to define clear actuating mechanism accommodating space therebetween.

5. A sewing machine as set forth in claim 1 in which said fastening means for maintaining said bracket arm and bed in fixed predetermined relationship includes locating pin means for accurately orienting said bracket arm and bed, and clamping means for maintaining said parts in assembled relation.

6. A sewing machine as set forth in claim 5 in which said means for fastening said bracket arm and bed in fixed predetermined relationship includes a locating pin extending between each of said pairs of interengaging bosses, and clamping means effective between each of said interengaging pairs of bosses for maintaining said parts in assembled relation.

7. A sewing machine as set forth in claim 1 in which said means for securing said sewing head and bracket arm together includes separate threaded fastening means for securing said parts together at spaced locations thereon, one of said parts being formed with a clearance aperture accommodating one of said threaded fastening means therethrough for angular adjustment of said sewing head relatively to said bracket arm about an axis defined by the other of said threaded fastening means.

8. A sewing machine frame including a bed formed with a work supporting surface and carrying a loop taker which defines relatively to said work supporting surface a restricted area through which a needle must reciprocate for cooperation with said loop taker in the formation of stitches, a bracket arm formed with means for supporting mechanisms above said bed, and a sewing head carrying an endwise reciprocable needle adapted to cooperate with said loop taker in the formation of stitches, a first set of planar mating surfaces formed on said bracket arm and substantially perpendicular to the work supporting surface on said bed, a second set of planar mating surfaces formed on said sewing head and substantially mutually perpendicular to the first set of planar mating surfaces on said bracket arm, fastening means for securing said first set of planar mating surfaces of said bracket arm and bed in that fixed interrelationship in which said needle in said sewing head will reciprocate in a plane intersecting said restricted area on said work supporting surface, and fastening means for securing said second set of planar mating surfaces of said sewing head and bracket arm together with a limited capacity for adjustment within which the needle in said sewing head will reciprocate in a path intersecting said restricted area on said work supporting surface.

9. A sewing machine as set forth in claim 1 which in addition to said means for fastening said bracket arm to said bed includes a further interconnection between said bracket arm and said bed comprising blade elements formed on said bracket arm and on said bed, said blade elements being oriented in planes substantially parallel to said first set of planar mating surfaces and being shaped to interdigitate in spaced relation to each other when said fastening means is effective, and locating pin means secured in a position extending transversely across said interdigitated blade elements.

10. A sewing machine as set forth in claim 3 which in addition to said means fastening said bracket arm to said bed includes a further interconnection between said bracket arm and said bed comprising interdigitated labyrinth means formed on said bracket arm and on said bed including elements projecting from said bracket arm and said bed in planes substantially parallel to said first set of planar mating surfaces, said labyrinth means being arranged in spaced interdigitated relation at the opposite side of the plane containing said first set of planar mating surfaces when the bracket arm and bed are united by said fastening means, axially aligned apertures formed transversely through said interdigitated labyrinth means, and a pin secured in said aligned apertures for locking said labyrinth means together. 

1. A sewing machine frame including a bed carrying a stitch forming loop taker and formed with a work supporting surface, a bracket arm formed with means for supporting mechanism above said bed, and a sewing head carrying an endwise reciprocable needle adapted to cooperate with said loop taker in the formation of stitches, a first set of planar mating surfaces formed on said bracket arm and on said bed, said first set of mating surfaces which are on said bed being substantially perpendicular to the work supporting surface thereon, means for fastening said first set of planar mating surfaces of said bracket arm and bed together in fixed predetermined relationship, a second set of planar mating surfaces formed on said sewing head and on said bracket arm, said second set of mating surfaces which are on said bracket arm being substantially mutually perpendicular to the first set of planar mating surfaces on said bracket arm, and means for securing said second set of planar mating surfaces on said sewing head and bracket arm together with limited capacity for adjustment therebetween in the plane of said second set of planar mating surfaces.
 2. A sewing machine frame as set forth in claim 1 and including means for transporting work transversely across said bed, in which said first set of planar mating surfaces extend longitudinally on said bed.
 3. A sewing machine frame as set forth in claim 2 in which the plane containing said first set of planar mating surfaces is offset transversely on said bed completely to one side of said loop taker therein.
 4. A sewing machine as set forth in claim 3 in which said first set of planar mating surfaces is formed on interengaging pairs of bosses located on said bed and on said bracket arm respectively, said interengaging of pairs of bosses being spaced apart longitudinally of said bed to define clear actuating mechanism accommodating space therebetween.
 5. A sewing machine as set forth in claim 1 in which said fastening means for maintaining said bracket arm and bed in fixed predetermined relationship includes locating pin means for accurately orienting said bracket arm and bed, and clamping means for maintaining said parts in assembled relation.
 6. A sewing machine as set forth in claim 5 in which said means for fastening said bracket arm and bed in fixed predetermined relationship includes a locating pin extending between each of said pairs of interengaging bosses, and clamping means effective between each of said interengaging pairs of bosses for maintaining said parts in assembled relation.
 7. A sewing machine as set forth in claim 1 in which said means for securing said sewing head and bracket arm together includes separate threaded fastening means for securing said parts together at spaced locations thereon, one of said parts being formed with a clearance aperture accommodating one of said threaded fastening means therethrough for angular adjustment of said sewing head relatively to said bracket arm about an axis defined by the other of said threaded fastening means.
 8. A sewing machine frame including a bed formed with a work supporting surface and carrying a loop taker which defines relatively to said work supporting surface a restricted area through which a needle must reciprocate for cooperation with said loop taker in the formation of stitches, a bracket arm formed with means for supporting mechanisms above said bed, and a sewing head carrying an endwise reciprocable needle adapted to cooperate with said loop taker in the formation of stitches, a first set of planar mating surfaces formed on said bracket arm and substantially perpendicular to the work supporting surface on said bed, a second set of planar mating surfaces formed on said sewing head and substantially mutually perpendicular to the first set of planar mating surfaces on said bracket arm, fastening means for securing said first set of planar mating surfaces of said bracket arm and bed in that fixed interrelationship in which said needle in said sewing head will reciprocate in a plane intersecting said restricted area on said work supporting surface, and fastening means for securing said second set of planar mating surfaces of said sewing head and bracket arm together with a limited capacity for adjustment within which the needle in said sewing head will reciprocate in a path intersecting said restricted area on said work supporting surface.
 9. A sewing machine as set forth in claim 1 which in addition to said means for fastening said bracket arm to said bed includes a further interconnection between said bracket arm and said bed comprising blade elements formed on said bracket arm and on said bed, said blade elements being oriented in planes substantially parallel to said first set of planar mating surfaces and being shaped to interdigitate in spaced relation to each other when said fastening means is effective, and locating pin means secured in a position extending transversely across said interdigitated blade elements.
 10. A sewing machine as set forth in claim 3 which in addition to said means fastening said bracket arm to said bed includes a further interconnection between said bracket Arm and said bed comprising interdigitated labyrinth means formed on said bracket arm and on said bed including elements projecting from said bracket arm and said bed in planes substantially parallel to said first set of planar mating surfaces, said labyrinth means being arranged in spaced interdigitated relation at the opposite side of the plane containing said first set of planar mating surfaces when the bracket arm and bed are united by said fastening means, axially aligned apertures formed transversely through said interdigitated labyrinth means, and a pin secured in said aligned apertures for locking said labyrinth means together. 